300 BULLETIN 45, UNITED STATES NATIONAL MUSEUM. 



Anteiiiiie lO-jointed, the scape snbclavate, slightly curved at base, 

 in both sexes terminating- in a 5-jointed club, the funiclar joints vary 

 but the first in both sexes is usually minute, the second and third sub- 

 ecjual, cylindric, in 9 , while in the S the second is enlarged, swollen, 

 the third vScarcely half as large, thinner and obli(|uely truncate at apex. 



Thorax subovoid, convex, the mesonotum rarely li times as long as 

 wide, with or without furrows; scutellum transversely elevated, convex 

 or cushion shaped, separated from the mesonotum by a transverse 

 depression or furrow; metathorax sliort, the metajjleura bounded above 

 by a carina. 



Wings veinless. 



Abdomen, in 9 , pointed-ovate, depressed, G-jointed, the first joint 

 petioliform, striated, the second longer than the following together, 

 smooth, with 2 oblong foveohe at base, in S oblong oval, 7- or 8- jointed. 



Legsclavate, the basal joint of hind tarsi about thrice as long as the 

 second. 



Distinguished from Plati/gaster by the shorter, rarely distinctly 

 grooved mesonotum, broader head, different antenniie, and the higher, 

 more convex, or cushioned-shaped scutellum, which has a deep trans- 

 verse impression all across the base. 



TABLE OF SPECIES. 

 FEMALES. 



Mesonotal fnrrows outire 6 



Mesouotiil fiUTDWs indic-atcd only posteriorly 3 



Mesonotum without trace of furrows, or tii<^ faintest trace of them posteriorly. 



Vertex not transversely acicnla ted 2 



Vertex transversely acicnlated. , 

 Coxa* black. 

 Legs black or brown-black. 

 Anteuna' black; pedicel as long as the two following joints united and 

 much thicker, the tip pale; first joint of fuuicle small, second and 

 third larger, nearly equal, the second slightly the larger, fourth 

 transverse; club joints, except the last, as broad as long. 



P. SALICICOLA 



AnteunaO>rown-black ; pedicel much longer than the two following 

 joints unitetl and much stouter; joints one and two of funide vei-y 

 small, nearly equal, the third slightly larger, fourth transverse; 

 club joints, except the last, only slightly longer than thick. 



P. DIPLOSIDIS 



CoxiP dark rufous or piceous. 



Legs rufous, the tarsi yellowish, femora and tiba^ often dusky. 



Scape black, sometimes ]>ale at base and apex, llagellum dark brown; 

 pedicel as long as the two following joints united and stouter; 

 joints one and three of funicle minute, the second slightly larger, 

 fourth longer than wide; dub joints except the last, very slightly 

 wider than long P. baccharicoi^ Aahm. 



Front legs, all trochanters and tarsi honey-yellow, sometimes the front 

 femora and tn>ia' dusky, middle and jxisterior femora and tibia^ dark 

 brown or black; sometimes all the legs pale brown. 



